Tropical Storm Champi formed over the Western North Pacific Ocean east of Guam on Thursday. At 5:00 p.m. EDT on Thursday the center of Tropical Storm Champi was located at latitude 11.6°N and longitude 155.8°E which put the center about 795 miles (1285 km) east of Guam. Champi was moving toward the west-northwest at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 999 mb.
Typhoon Watches are in effect for Guam, Rota, Tinian, and Saipan.
A low pressure system over the Western North Pacific Ocean east of Guam strengthened on Thursday and the Japan Meteorological Agency designated the system as Tropical Storm Champi.
Even though Tropical Storm Champi was strengthening on Thursday, the distribution of thunderstorms in Champi was asymmetrical. Thunderstorms were occurring in bands in the western and southern parts of Champi’s circulation. Bands in the eastern and southern parts of Tropical Storm Champi consisted primarily of showers and lower clouds. Storms near the center of Champi began to generate upper level divergence that pumped mass away to the west of the tropical storm. The removal of mass caused the surface pressure to start to decrease.
The distribution of wind speeds in Tropical Storm Champi was also asymmetrical. Winds to tropical storm force extended out 85 miles (135 km) in the southern half of Champi’s circulation. The winds in the northern part of Tropical Storm Champi were blowing at less than tropical storm force.
Tropical Storm Champi will move through an environment that will be favorable for intensification during the next 24 hours. Champi will move over water where the Sea Surface Temperatures are near 28°C. It will move under the southern part of an upper level ridge that is over the Western North Pacific Ocean. The upper level ridge will produce easterly winds that will blow toward the top of Champi’s circulation. Those winds will cause some vertical wind shear. The vertical wind shear will inhibit intensiciation, but the wind shear will not be enough to prevent intensification. Tropical Storm Champi will intensify during the next 24 hours. Champi could strengthen to a typhoon by Friday night.
Tropical Storm Champi will move around the southern side of a high pressure system that is over the Western North Pacific Ocean. The high pressure system will steer Champi toward the west-northwest during the next 24 hours. On its anticipated track, Tropical Storm Champi will move toward the Marianas. Champi could reach the Marianas in 48 hours.
Tropical Storm Champi is likely to be a typhoon when it reaches the Marianas. Champi is likely to bring strong winds and heavy rain to Guam, Rota, Tinian and Saipan. Heavy rain is likely to cause flash floods in some locations.